Device was used for treatment, not diagnosis.Additional product codes: hrs hwc.(b)(6) device history records was conducted.The report indicates 02.231.265 ¿ 9501984, manufacturing site: (b)(4), manufacturing date: 26.May.2015, expiry date: - no ncrs were generated during production.Review of the device history record(s) showed that there were no issues during the manufacture of the product that would contribute to this complaint condition.An product investigation summary was performed.The investigation of the complaint articles has shown that: we have forwarded the received parts to the responsible person in the sustaining engineering department for evaluation, here are the findings: the x-ray revealed that 3 va-locking-screws were unlocked and backed out of the head of the plate, but, it could not confirm how many screws were loose or the associated part numbers.Closer examination of the article 02.231.265 (lot 9501984), article 02.231.270 (lot 9361254) and article 02.231.255 (lot 9603458) va locking screws reveals an extensive amount of thread deformation of the locking screw heads.However, afterwards it cannot be defined if these damage occurred during the insertion, in-situ or during the extraction of the screws, therefore, the exact cause for the back out of the screws could not be determined.Based on the surgical technique review the final tightening of the va locking screws must be done by hand using the t-handle with torque limiting function 6 nm.Furthermore, the surgical technique states; ¿for off-axis drilling, insert the drill bit through the cone-shaped end of the drill sleeve at the desired angle to prevent drilling beyond 15 degrees".If a va-locking-screw is insert beyond 15 degrees the screw won't probably lock, although, the t-handle with torque limiting function 6 nm was used.Not following these advices above might have supported the back out of the screws.The back out of at least 3 va-locking-screws within the construct has significantly minimized the strength of the entire construct compounded.However, evaluating the provided complaint description, provided x-ray as well as locking at the returned product no clear root cause can be determined and there might be multiple causes that lead to the clinical hazard.The returned devices were received clean, and besides the marks of use, the screws show no visual deviations.If information is obtained that was not available for the initial medwatch, a follow-up medwatch will be filed as appropriate.
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